I'm not sure how far into the first actual act I am right now (just met up with the cute berzerker - eek!), but I'm enjoying it. Performance is good, the game is gorgeous, and the checkpoint system means I can play the game at my pace.
I simply cannot tell you how important that feature is to me.
I'm not playing for long stretches at a time, rather, a bit here and there as it suits me. I'm getting more adept at controlling the game; roadie rush, covering, switching positions, etc. Its been so long since I played a shooter I'm actually going on Casual, and its good. Very nice.
http://www.flickr.com/photos/8803359@N08/2294574669/
http://www.flickr.com/photos/8803359@N08/2292991341/
By the way, I've mentioned this before, but I'll say it again; Gears runs well on my computer. I'm very happy with it. I can't remember what my current settings are, but its good looking, at 1280x1024, and plays pretty smoothly over all.